1. Field of the Invention
This invention relates to a deposit-resistant and ORI-inhibited motor fuel composition, and to a concentrate formulation for use in motor fuel compositions. More particularly, this invention relates to a deposit-resistant and ORI-inhibited motor fuel composition comprising: (I) the reaction product of a dibasic acid anhydride, a polyoxyalkylene diamine, and a hydrocarbyl polyamine; and (II) a mixture of a major amount of polyisobutylene ethylene diamine and a minor amount of polyisobutylene. Concentrates of the instant invention comprise components (I) and (II) in admixture with a hydrocarbon solvent to facilitate introduction of the concentrate into a motor fuel composition.
Combustion of a hydrocarbon motor fuel in an internal combustion engine generally results in the formation and accumulation of deposits on various parts of the combustion chamber as well as on the fuel intake and exhaust systems of the engine. The presence of deposits in the combustion chamber seriously reduces the operating efficiency of the engine. First, deposit accumulation within the combustion chamber inhibits heat transfer between the chamber and the engine cooling system. This leads to higher temperatures within the combustion chamber, resulting in increases in the end gas temperature of the incoming charge. Consequently, end gas auto-ignition occurs, which causes engine knock. In addition, the accumulation of deposits within the combustion chamber reduces the volume of the combustion zone, causing a higher than design compression ratio in the engine. This, in turn, also results in serious engine knocking. A knocking engine does not effectively utilize the energy of combustion. Moreover, a prolonged period of engine knocking will cause stress fatigue and wear in vital parts of the engine. The above-described phenomenon is characteristic of gasoline powered internal combustion engines. It is usually overcome by employing a higher octane gasoline for powering the engine, and hence has become known as the engine octane requirement increase (ORI) phenomenon. It would therefore be highly advantageous if engine ORI could be substantially reduced or eliminated by preventing or modifying deposit formation in the combustion chambers of the engine.
Another problem common to internal combustion engines relates to the accumulation of deposits in the carburetor which tend to restrict the flow of air through the carburetor at idle and at low speed, resulting in an overrich fuel mixture. This condition also promotes incomplete fuel combustion and leads to rough engine idling and engine stalling. Excessive hydrocarbon and carbon monoxide exhaust emissions are also produced under these conditions. It would therefore be desirable from the standpoint of engine operability and overall air quality to provide a motor fuel composition which minimizes or overcomes the above-described problems.
A third problem common to internal combustion engines is the formation of intake valve deposits. Intake valve deposits interfere with valve closing and eventually result in valve burning. Such deposits interfere with valve motion and valve sealing, and in addition reduce volumetric efficiency of the engine and limit maximum power. Valve deposits are usually a result of thermal and oxidative unstable fuel or lubricating oil oxidation products. Hard carbonaceous deposits collect in the tubes and runners that conduct the exhaust gas recirculation (EGR) gases. These deposits are believed to be formed from exhaust particles which are subjected to rapid cooling while mixing with the air-fuel mixture. Reduced EGR flow can result in engine knock and NO.sub.x emission increases. It would therefore be desirable to provide a motor fuel composition which minimizes or overcomes the formation of intake valve deposits.
It is the object of this invention to provide a deposit-resistant and ORI-inhibited motor fuel composition, as well as a hydrocarbon solvent-based concentrate composition which may be added to motor fuel to produce such a motor fuel composition. Motor fuel compositions of the instant invention exhibit both reduced ORI and increased resistance to carburetor intake valve, intake manifold, and EGR system deposit formation in comparison with conventional motor fuel compositions.
2. Information Disclosure Statement
Co-assigned U.S. Pat. appl. Ser. No. 000,253, filed Jan. 2, 1987 (Sung et al.) (D#78,650) discloses a novel polyoxyalkylene diamine compound of the formula: ##STR1## where c has a value from about 5-150, b+d has a value from about 5-150, and a+e has a value from about 2-12. Motor fuel compositions comprising the novel polyoxyalkylene diamine, alone or in combination with a polymer/copolymer additive are also disclosed.
Co-assigned U.S. Pat. appl. Ser. No. 000,230, filed Jan. 2, 1987 (Sung et al.) (D#78,679) discloses a motor fuel composition comprising the reaction product of the polyoxyalkylene diamine of U.S. Pat. appl. Ser. No. 000,253, a dibasic acid anhydride, and a hydrocarbyl polyamine. An optional additional polymer/copolymer additive with a molecular weight of 500-3500 may also be employed in conjunction with the reaction product additive.
Co-assigned U.S. Pat. No. 4,659,337 (Sung et al.) discloses the use of the reaction product of maleic anhydride, a polyether polyamine containing oxyethylene and oxypropylene ether moieties, and a hydrocarbyl polyamine in a gasoline motor fuel to reduce engine ORI and provide carburetor detergency.
Co-assigned U.S. Pat. No. 4,659,336 (Sung et al.) discloses the use of the mixture of: (i) the reaction product of maleic anhydride, a polyether polyamine containing oxyethylene and oxypropylene ether moieties, and a hydrocarbyl polyamine; and (ii) a polyolefin polymer/copolymer as an additive in motor fuel compositions to reduce engine ORI.
Co-assigned U.S. Pat. No. 4,631,069 (Sung) discloses an alcohol-containing motor fuel composition which additionally comprises an anti-wear additive which is the reaction product of a dibasic acid anhydride, a polyoxyisopropylene diamine of the formula ##STR2## where x has a value of 2-68, and an n-alkyl-alkylene diamine.
Co-assigned U.S. Pat. No. 4,643,738 (Sung et al.) discloses a motor fuel composition comprising a deposit-control additive which is the reaction product of a dibasic acid anhydride, a polyoxyisopropylene diamine of the formula ##STR3## where x has a value of 2-50, and an n-alkyl-alkylene diamine.
U.S. Pat. No. 4,604,103 (Campbell) discloses a motor fuel deposit control additive for use in internal combustion engines which maintains cleanliness of the engine intake system without contributing to combustion chamber deposits or engine octane requirement increase (ORI). The additive disclosed is a hydrocarbyl polyoxyalkylene polyamine ethane of molecular weight range 300-2500 having the formula ##STR4## where R is a hydrocarbyl radical of from 1 to about 30 carbon atoms; R' is selected from methyl and ethyl; x is an integer from 5 to 30; and R" and R'" are independently selected from hydrogen and .dbd.(CH.sub.2 CH.sub.2 NH.dbd.).sub.y .dbd.H where y is an integer from 0-5.
Co-assigned U.S. Pat. No. 4,581,040 (Sung et al.) discloses the use of a reaction product as a deposit inhibitor additive in fuel compositions. The reaction product is a condensate product of the process comprising:
(i) reacting a dibasic acid anhydride with a polyoxyisopropylenediamine of the formula ##STR5## where x is a numeral of about 2-50, thereby forming a maleamic acid;
(ii) reacting said maleamic acid with a polyalkylene polyamine, thereby forming a condensate product; and
(iii) recovering said condensate product.
U.S. Pat. No. 4,357,148 (Graiff) discloses a motor fuel additive useful in controlling ORI which is the combination of (a) an oil-soluble aliphatic polyamine containing at least one olefinic polymer chain, and (b) a polymer, copolymer, or corresponding hydrogenated polymer or copolymer of a C.sub.2 -C.sub.6 mono olefin with a molecular weight of 50-1500.
U.S. Pat. No. 4,166,726 (Harle) discloses a fuel additive which is the combination of (i) the reaction product of an alkylphenol, an aldehyde, and an amine, and (ii) a polyalkylene amine.
U.S. Pat. No. 3,960,515 (Honnen) and U.S. Pat. No. 3,898,056 (Honnen) disclose the use of a mixture of high and low molecular weight hydrocarbyl amines as a detergent and dispersant in motor fuel compositions.
U.S. Pat. No. 3,438,757 (Honnen et al.) discloses the use of hydrocarbyl amines and polyamines with a molecular weight range of 450-10,000, alone or in combination with a lubricating mineral oil, as a detergent for motor fuel compositions.